Air brake



Mgy 23, 1939. c. A. CAMPBELL AIR'BRAKE 3 Sheetvs-Shee;

Filed Aug. 2, 1938 May 23, 1939.

c'. A. CAMPBELL AIR BRAKE Filed Aug; 2, `1933 s sheets-sheet 2 :inventor@mL/mammina@ dttomegs M? 23, 1939- c. A. CAMPBELL 2,159,687

AIR BRAKE Filed Aug. V2, I1938 3 Sheets-Sheet 3 nnentor @53m/zend.

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dttornegs 1, Patented May 23, 1939d 13 Claims. 'I'his invention relatesto air .i brakes, and particularly to brake controlling means where a`lfcontrol chamber and master relay are used.

. `Inmodern deceleration controlled brakes, and

`V1si1rrilar systems involving some type of automatic a. modulation ofbraking pressure (schedule HSC irtions of the engineers brake valve, afirst service Isometimes called slowservice) position and a F secondservice, which is a fast Service position. The` first develops" controlchamber ,pressure slowly so that the engineer may exercise a graduatedcontrol below that degree of applica- 1 a `tionat which the decelerationcontroller functions a vV-to assume control. What that `degree is,depends i on train speed. The second-position builds up control chamberpressurevery rapidlyand is the one used when rapid straight airapplicationand l 'Uprompt assumption of control by the decelerometer aredesired.

u In the early installations, the brakes `commenced to apply with veryslight rise of brake @cylinder pressure, but the application of return idfspringS, anti-rattlingttings,multiple-shoe Clasp a y. i lbrakes, andother refinements found desirable as wthedesign advanced, has changedthe situation.V

` .At present the brakes do not apply until a brake l cylinder pressureof fifteen to twenty pounds gage (for example) is reached. This entailsa lserious time lagin slow 'service position between motion oftheengineers brake valveto such positionand the initial braking effect onthe wheels.

. `The prime purpose `of the present` invention isto provide meanscomprising a measured inshot 1" \3`5`""device which `upon the initialmovement of the l engineers brakevalve to slow servicevposition, a lvill immediately establish sufcient pressure `in Y a the control chamberto start effective braking f @at ailowvalue. The device is so contrivedas not 'to repeat its function until reset as an incident `tosubstantially complete release of the brakes. Thus the device operatesonce on initial motion to either service position, and thereafter isinert "so long as the application continues. Hence, the engineer maygraduate the brake application by I increasing or diminishing controlchamber pressure, without interference by the measured inshot device,but as soonas he releases the brakes the measured inshot device is resetand refcharged ready to expedite' commencement of the i. `next slowapplication.

, 3 a ,aAn important aspect of the invention, particu--` L a `larly forhigh speed service is that a single device l affects all the brakesthroughout thel train` at yjthe same time and inthe same degree. Thishas being typical), there are usually two service posii eTENT OFFICE aAIR nimmt i CharlesA. Campbell, Watertown, N. Y., assigner 4to The NewYork Air Brake Company, `a corporation of New Jersey .i

` `Application August 2, 1938, Serial No. 222,690

` (o1. sosfai) greatpractical importance Vbecause it assures harmoniousaction of all the brakes.

While the invention may .be used with any system having a` controlchamber and master relay, I shall describe it as^ embodied in schedule5'1"" l-ISC, to indicate how it `may be related `to a decelerationcontrolled electropneumatic system operating on the straight airprinciple but with associated automatic brake pipe," vent valve andapplication valve to provide for automatic brak- 10" ing on occasion.

In-the drawings: i

Figure l is a vertical axial section through the engineers brake valveand measured inshot valve withV pipe connections.

shown. f

Fig. 2 is a similar View of the application valv vent valve, reset valveand pipe connections. Normal or. running positions are shown.

Fig. 3 is a similar view showing the pneumatic 20 relay and `theassociated electric relay switch in release position and thedecelerometer rin normal (running) position. Piping and electricconnections are indicated.

Note-Figs. 2, 1 and s when assembled in the 25'* order stated from leftto `right form a complete diagrammatic illustration of the head-end orcontrolling portion of the `I-ISC system with the present invention`incorporated.

Figs. 45, 6, 7 are fragmentary views showing 30v the rotary valve of theengineers brake valve (Fig. l) in the following `functional positions,respectivelyz` lap, slow service, fast service, and (automatic)emergency.

Fig. 8 shows the measured inshot valve of Fig. 1 35 in the positionwhichit assumes when the rotary valve is initially placed in slow serviceposition (Fig. 5)` and in which position it remains until the engineersbrake valve is returned to release position (Fig. 1). 40

Fig. 9 shows the reset valve of Fig. 2 set to release the brakes andcause recharge of the autodrawings, there are two pipes which runthroughout the length of the train, namely, the brake pipe orsupervisory line .I I which may control the brakes on the automaticprinciple, and a control Release position is 15" for a clearunderstanding.`

pipe I2 which controls the brakes on the straight air principle. That isto say, the brake pipe II is normally charged and applies the brakesupon the reduction of pressure in the pipe; the control pipe I2 isnormally vented and applies the brakes in proportion to pressuresdeveloped in the control pipe by operation of the engineers brake valve,or by operation of the application valve.

The control valve mechanism on the cars is not illustrated in thedrawings. It may assume various forms, but the so-called D-22 controlvalve, standard in the industry, may be used. This comprises a triplevalve and a change-over device such as either the triple valve or thecontrol pipe may assume control of the local relay. The relay valvenormally responds to pressure in the control pipe I2, and the triplevalve responds only to pressure in the brake pipe I I. When the triplevalve responds to reduction of pressure in the brake pipe, it assumescontrol of the relay, but" not to the exclusion oi the control pipewhich may resume control if an effective braking pressure isldevelopedin the control pipe I 2. These features are known in the art and are nota part of the present invention, but are mentioned here The elementsillustrated in the drawings of the present application are carried onthe leading or propelling unit. It should be understood that this unitalso carries control valves connected with the control pipe and brakepipe for regulating the application of brakes on the propelling units.

'I'hese valves are not illustrated in the drawings.

The engineer controls the train through an engineers brake valvegenerally indicated by the numeral I3, Fig. 1, which has five functionalpositions: a combined release and running position, shown in Fig. 1, inwhich the control pipe is vented to atmosphere, as will later beexplained; a lap position (Fig. 4) in which all ports are blanked; aslow service position (Fig. 5) in which air from the main reservoir issupplied at a restricted rate to the control chamber, as willhereinafter be described; a fast service position (Fig. 6) which isfunctionally similar to slow service except that air is supplied to thecontrol chamber at a rapid rate; and an emergency position (Fig. 7),which in the example illustrated is initially of the automatic type.

In emergency operation the brake pipe is vented through the response ofan automatic vent valve indicated as a whole by the numeral I4 (Fig. 2),which will also respond to reduction of brake pipe pressure produced byoperation of conductors valves, etc. At such times, charging flow to thebrake pipe is interrupted by an application Valve generally indicated bythe numeral I5, also shown in Fig. 2, the application valve then servingto supply main reservoir air to a straight air emergency pipe connectedwith the control chamber and also to the loading cylinder of thedecelerometer indicated generally by the numeral I6'- (Fig. 3). Theeffect of this is to develop a brake applying pressure in the controlchamber at a rather rapid rate andV to set the decelerometer to regulatethe brakes in such a way as toproduce the higher of two decelerationrates, the lower of which is effective both in slow service and in fastservice manipulation. Thus when the application valve I5 and the ventvalve I4 start a strictly automatic emergency application through theautomatic side of the system (pipe II) they also initiate a straight airapplication by developing pressure in the control chamber. This secondor straight airfunction will take control at the control valves, unlessdefeated by a ruptured control pipe or other defect, and will bemodulated by the decelerometer.

The engineers brake valve I3 and the application valve I5 are related tothe decelerometer I6 through a double throw check valve I'I so that ifeitherfunctions to deliver braking pressure it will be connected withthe control chamber. The air so supplied by either passes under controlof the decelerometer I6 to the control chamber I 8. The pressuredeveloped in this control chamber is subject to a modulating control(reduction) by the decelerometer I 6, to release the application as thecoeicient of brake shoe friction increases, so that uniform decelerationwill be had.

Pressure in the control chamber I8 controls the pressure in the controlpipe I2 through a relay mechanism made up of two units, a pneumaticrelay I9 and an electric relay switch 2l which last operates magnetvalves throughout the train to admit and exhaust air to and from thecontrol pipe I2.

Upon the development of braking pressure in the control chamber I8, thepneumatic relay indicated as a whole bythe numeral I9, moves to a lapposition and there stalls if the electric relay switch is effective, asit should be, to develop braking pressure in the control line I2. If theelectric relay switch indicated as a whole by the numeral 2|, or thedevices controlled thereby, should fail to function, then the pneumaticrelay I9 will move further to an active position and supply mainreservoir air to the` control line` I2.

The above general description identifies the main control components ofthe system as heretofore used. To this has been added a measured inshotvalve, generally indicated by the numeral 22 (Fig. 1). This valve isclosely associated with the engineers brake valve I3 and is interposedin the path of flow from the engineers brake valve to the controlchamber I8. Its function is to accumulate under running conditions adefinite volume of air under supply pressure and upon the initiation ofa service application, whether slow or fast, to deliver this charge ofair rapidly to the control chamber I8. The measured volume` of airstored by the inshot valve 22 is Yso chosen, with reference to thevolume of the control cham.- ber I8, that control chamber pressure willimmediately rise to a value which will bring the brakes to the point ofapplication without, however, developing a substantial braking pressure.

The inshot valve 22 is so arranged that it does not interfere with, butin fact actually accelerates the fast service application, and it isfurther so contrived that it cannot reset until the brakes aresubstantially released.

The main reservoir is indicated at 23 and the main reservoir pipe at 24.This pipe has a nurnber of branches leading to the application valve,the engineers brake valve and the master relays, as clearly shown in thedrawings'.

Referring first to Fig. l and Figs. 4 to 7, inelusive, the structure ofthe engineers brake valve will be described.

The main reservoir connection to the engineers brake valve leads to therotary valve chamber 25 which is formed in the pipe bracket member 26 ofthe engineers brake valve I3. The rotary valve2l' is manipulated bymeans of stem 28 and handle 29 in the usual manner. The seat for the`rotary valve has three ports: an emergency port 3|, by means of whichthe vent valve I 4 and the application valveV I5 are controlled; acontrol chamber port 32, which is the connectionto the control chamberI8, such connection Fig. 1, the cavity 34 in the rotary valve connectsthe control chamber port 32 with the exhaust port 33. 'I'he emergencypo-rt 3| isI blanked.

In lap position, Fig. 4., al1 ports are blanked by therotary valve. i

In slow service position, Fig. 5, the ports 3| and 33 are blanked` and arestricted port 35 through the rotary valve supplies main reservoir airfrom the rotary valve chamber to the control chamber port 32.

In fast service position, Fig. 6, a larger through port 36 performs thesame functionof admitting main reservoir air to the control chamber porti 32, but being much larger, admits it at a rapid zeI 201 Trate.

September 9, 1935, will be described. The emergency port 3| of theengineers brake valve is conpipe connections are made.

nectedby way of pipe 38 to a port 4| in the pipe bracket 39. This pipebracket sustains the application valve and the vent valve and to thisall The brake pipe II is connected to this pipe bracket and communicateswith twin ports 42 in the slide valve seat of the application valve I5,and also with the passage 43 of the vent valve I4. The main reservoirpipe 24 is connected to the bracket 39 and communicates with a port 44which leads to the slide valve chamber 45 of the application valve andalso to chamber 46 of the reset valve. In this chamber, the rotary resetvalve 41 is mounted. Its porting will be described later.

Reverting now to the vent valve shown at the right of Fig. 2, the mainvent valve is a spring loaded cup valve 48 which when relieved ofpneumatic loading on its rear face, will open in rehsponse to brake pipepressure andvent the brake pipe directly to atmosphere. This operationis ordinarily produced by the opening of a pilot valve 49 which servesto vent the space to the rear of the cup valve directly to atmosphere.

The pilot valve 49 is also spring seated and is opened by the diaphragml5| when brake pipe pressure which is `communicated through brake pipeport 43 or pressure in the emergency port 4| is sharply reduced. At suchtime, the pressure in the quick action chamber 52 predominates andforces the diaphragm upward to open the pilot valve. The chamber 52 ischarged from the brake pipe through the charging port 53. A check valve54 which is spring loaded in its closing direction and which is forcedopen when the pilot valve 49 opens', is provided to prevent flow undernormal conditions from the port 4| to the space above the diaphragm 5|.It opens to permit `flow in the reverse direction so that the emergencyport 3| 4I may control the vent valve directly.

The check valve 55 and the choke 56 control connection from the brakepipe port 43 to the space above the diaphragm 5I. They permit `rapidflow to the brake pipe from this space so that the diaphragm willrespond to a sudden reduction of brake pipe pressure, but they controlthe build up of pressure in the space above the diaphragm 5| in relationto the charging port 53.

This vent valve` as above very generally describedis typical of anydevice which in response ,to a sudden reduction of brake pipe pressureor to a sudden reduction of pressure in emergency port 3|, 4|, will ventthe brake pipe freely and rapidly to atmosphere.

The application valve I5, which is shown to the left inFig. 2, comprisesa slide valve 51 actuated by a piston 58 and biased by spring 59 to itslowermost position, shown in Fig. 2. 'Ihe space above the piston 58 isconnected by a passage l and cavity 52 in the reset valve 4l with thepassage 4| and, consequently, with the emergency port 3| of theengineers brake valve.

A charging groove 63 which leads around the edge of piston 58 when thelatter is in its normal lower position, keeps the ports 3|, 4I, 3|charged under normal'conditions.l This charging groove is overtraveledand closed if the piston 58 moves upward.

Under running conditions, the application valve feeds main reservoir airfrom the slide valve chamber 45 to the ports 42 and hence to the brakepipe, and at the same time the straight air emergency port 54 formed inthe seat of the slide valve is vented to atmosphere by cavity 65 in theslide valve and exhaust port 65 in its seat. If the piston 58 movesupward in response to an emergency actuation of the engineers brakevalvev I3, or in response to an emergency venting operation of the ventvalve I4, the slide valve blanks the ports 42, terminating the feed tothe brake pipe and at the same time, exposes emergency straight air port54 so that main reservoir air is admitted to the port 64 which, ashereafter explained, initiates an emergency application on the straightair side of the system.

In order to reset the piston 58 after an automatic emergency, whethercaused by manipulation of the engineers brake valve or by suddenreduction of brake pipe pressure produced by rupture of the brake pipeII or the operation of a conductors valve,some means must be provided toreestablish the pressure above the piston 58. The rotary valve 4l whichmay be turned through the stem 5l and handle 68, has a reset -positionshown in Fig. 9 in which a through port 69 `admits main reservoir airfrom the valve chamber 46 to the port BI. This, as explained, leads tothe space above the piston 58. The valve 4l is not left in resetposition but is restored to the running position of Fig. 2 as soon asthe application valve has reset and has reestablished the chargingconnection through ports 42 to the brake pipe.

This arrangement is considered better than providing a reset port in theengineers brake valve. The latter arrangement, however, is a knownalternative in systems of this general class.

The straight air emergency port 34, previously mentioned, leads througha choke 'II and pipe 'I2 to the lower of the two end connections of thecheck valve I'I and leads also to the end of the loading cylinder 13 ofthe decelerometer IB. The pipe I4 leads from thepipe bracket 25 of theengineers brake valve I3 to the upper end connection of the double checkvalve` II. Thus, the check valve connects whichever of the pipes 'I2 and'I4 is under pressure to a pipe 'I5 connected to the side of the doublecheck valve and lti leading to the inlet port 16 of the decelerometervalve (see Fig. 3).

The decelerometer I6 is shown only in fragmentary form but the essentialcomponents are L illustrated. Its controlling element is a balancedpiston valve 11 which connects the control chamber port 18 selectivelywith the inlet port 16 and the exhaust port 19. The exhaust port 19leads to atmosphere through the usual retaining check valve 80.

The valve 11 is actuated by an inertia mass 8| which is guided onrollers, some of which appear at 82, to move in a path parallel with thedirection of travel of the train. When the mass moves forward relativelyto the train as the result of brake application, it reacts through lever83 upon the forward end of the valve 11, forcing the valve rearwardlyagainst the resistance of the spring 84. This spring is seated underinitial stress against a loading piston 85 which works in the cylinder13, lalready mentioned. When pressure is admitted to the cylinder 13through the straight air emergency pipe 12, the piston is forced to theleft, stressing the spring 84 more heavily and thus loading thedecelerometer to maintain a somewhat higher deceleration rate than thatmaintained in service applications.

The structure of the decelerometer is not claimed herein but forms thesubject matter of other applications, notably Serial No. 724,990, ledMay 10, 1934.

When pressure fluid is admitted to the pipe 15 from either the pipe 14(service application) or the pipe 12 (emergency application), it flowsby way of ports 16 and 18 to the control chamber I8. The pressure sodeveloped in the chamber i8 causes the application of the brakes. Thefunction of the decelerometer is to terminate the build up of controlchamber pressure when the desired deceleration rate is reached andthereafter to reduce control chamber pressure at such a rate as tomaintain the deceleration rate constant despite the rising coefcient ofbrake shoe friction, which is characteristic of falling train Thepressure in the control chamber i8 operates through a master relaymechanism compris- .ing a pneumatic relay I9 and an electric relayswitch 2|. These involve patentable features :which are described andclaimed in my application, Serial No. 724,989, filed May 10, 1934.

The pipe bracket 86 on which the relay mechanism is supported has a port81 connected by pipe 38 with the control chamber I8. It also includes amain reservoir port 89 to which the main reservoir pipe 24 is connectedand a control pipe port 9| to which the control pipe I2 is connected.The bracket also includes an exhaust port 92. The pneumatic relay is ofa type standard in the art and hence requires only a brief description.It includes a relay piston 93 which is subject on its upper face tocontrol pipe pressure acting in the chamber 94, and on its lower face tocontrol chamber pressure acting in the chamber 95. The lcheck valvesshown at 96 and 91 are loaded by- Dass check valves serving to connectthe control chamber and the control pipe directly for either directionof flow if an abnormally large pressure differential is built up betweenthem.

Connected to piston 93 is a stem 98 which carries pivoted to it a rockerarm. 95. This rocker arm functions to permit the exhaust valve IOIleading from chamber 94 to atmosphere via port 92, to open when thepiston is in its lowermost position. At this time the inlet valve |02 isclosed'. As the piston moves upward its first effect is to close theexhaust valve I0| and then force open the inlet valve |02, admittingmain reservoir air from port 89 to the chamber 94. However, the inletvalve oifers considerable resistance toopening, so that when the pistonmoves up and closes the exhaust valve, it normally stalls in what may bedescribed as a lap position.

Reliance is placed on the relay switch to develop the desired pressurein the control valve. This switch comprises a diaphragm |03 whichresponds to the differential between control pipe pressure acting inchamber |04 and control chamber pressure acting in the chamber |05. Theapplication switch |06 and the release switch |01 are both normallyopen. If control chamber pressure predominates, the diaphragm movesupward and closes the application switch; if control pipe pressurepredominates, the diaphragm moves downward and closes the releaseswitch. These switches control application and release circuitspartially indicated in the drawings at |08 and |09, which include magnetvalves on the various cars (not shown).

The application circuit magnet valves function when energized to admitair under pressure to the control pipe, and the release magnet valvesfunction when energized to vent pressure from the control pipe.V It willbe observed, therefore, that when pressure is established in the controlchamber |8, the electropneumatic side of the system operates to developa corresponding control pipe pressure throughout the length of thetrain. Similarly, when control chamber pressure is lowered the controlpipe pressure is correspondingly lowered. During these operations, themaster pneumatic relay I9 remains in lap position, but it will move toapplication position and assume control if the electric circuits fail tofunction. Should the pneumatic relay also fail to function, the bypasschecks 98 and 91 will permit direct control of the control pipe pressurewith a. moderate diierential.

The system abo-ve described embodies the general principles of myapplication, Serial No. 27,758, filed June 21, 1935, and, consequently,no novelty is here claimed either for the system or for those componentsof the system which have already been described as covered by priorapplications. The description of the system aspects is given to afford aproper background for the disclosureof the measured inshot valve whichis of general utility but which develops peculiar value and functions in`conjunction with a system of this general type.

The inshot valve, which is indicated generally at 22, is mounted at theside of the engineers brake valve I3 and its body is made up of twoparts, a main housing III and a cap I2. Between the members III and |I2is clamped a combined gasket and diaphragm I I3. 'I'he chamber I4 abovethe diaphragm is in free communication with the control chamber port 32of the engineers brake valve. The chamber |I5 below the diaphragm isvented to atmosphere in any suitable way, a convenient means being theexhaust port 33 from the engineers brake valve.

Clamped to the center of the diaphragm I I3 are the plates I I6 and I|1which stiften the center of the diaphragm and control its exure. One ofthese plates is formed integrally with a stem I|8 which` is directed inits longitudinal movements by a guide I| 9. The spring !2| urges thediaphragm upward with a force which will approximately balance apressure of 3 lbs. per square aisaesv' Y 5 inch acting on the diaphragm.'Whenthe dia- Vphragm is forced downward against the resistance`lloi'jrned in the stem I I8 is a through port |23` havinga lateralextension in the lower'end so located that when the diaphragm is'in itsupper position,

` fFg. l, the port is` blanked because within the l. guideway. `For lackof a better term, the valve r y When the diaphragm is forced to itslowermost .e position, Fig, 8, the port |23 communicates with thechamber|25 which is connected by a passage e |2`6with the pipe `14. Thispipe,asalready dethus provided will be called an intercepting valve.

"scribed, leads by `way of the double check valve I1 `and thedecelerometer |6 to thejcontrol cham- Below and partly surrounding thechamber is a closed measuring chamber |24 which is alternately andselectively connected with vthe main reservoir to accumulate a chargeand with the chamber |25 to deliver that charge to the control chamberI8. l

l l'rhe chamber H4 above the diaphragm ||3 and jthechamber |25 which isconnected with w |2 1:is 'lightly loaded' and is provided to Apermit 4o,instem ||`8` and which isA urged outward'by a spring 3| of sufficientstrength lto shift the double surein the chamber ||4 reaches 3 lb's.gage, as it"`will quite promptly, the diaphragm., moves `down and shiftsvalve |32A fromeitsjupper to its lower seat. During running conditions,the chamber |24 was charged tomain reservoir presbaek new duringre1ease. `cheek valve |28 is loaded'to resist a pressure higher thanthat to `which the diaphragm ||3 responds.

Thus, if the diaphragm ||3 starts to move downward under pressure of 3lbs. per square inch, a satisfactory loading for the valve |28 isthatwhich will cause lthe valve to open under a differential of about ward.y

The lower end of the stem |8 carries a thrust pin l29`which is guided toslide longitudinally trols communication to the chamber |25.

yA spring |35 urges the valve |32 toward the seat |34, while the thrustpin |23 will, upon descent of the diaphragm ||3, shift the valve to theother seat andhold itthere withsealing force. The rate of supply ofairthrough the port |31 is controlled by a choke |36.

Operation The operation of the system, as a whole has already beendescribed vanol's known in the art. 60`

` quires description in connection with slow service' The operation ofthe measured inshot valve reand fast service functions.

Slow service- The rotary valve is put` in the position of Fig. 5` sojthat main, reservoir air is fed` slowly to the port l32. As soon as thepresl |26,`pipe 14, double checkvalve |1,pipe 15 and the decelerometerwith the control chamber I8.`

vdropped below 3 lbs.

The volume of the chamber |24 is so chosen that the admission of thisvolume of air at main reser- Voir pressure will establish in the controlchamber I8 a pressure suflcient to initiate a brake application.Ordinarily, this desired pressure is of the order of fifteen to twentylbs. The pressure to be established is dependent upon thecharacteristics of the brake rigging and it requires only the choice ofaproper volume for chamber |24.

Fast .gemma- The operation in fast service is exactly the same so far asthe measured inshot valve is concerned, but the pressure in the AchamberH4 will rise so rapidly that the 5 lb. loading of the check valve |28will quickly be exceeded so that the valve |28 will open,"permittingmain reservoir air to flow by way of the engineers brake valve andchamber |25 directlyto the control chamber. e

The diaphragm ||3 remains in its lowermost position until controlchamber pressure has At that time, the brakes will have been released.Consequently, a service graduation by manipulation of the handle 29between lap, release and slow service positions can be carried out solong as the braking intensity does not cause the decelerometer |6 totake con,`` i i trol. Releasing ilow to theengineer's brakevvalve takesplace partly through the port |23 but also through the lightly loadedcheck valve |21.

v Emergency-If the engineers brake valve I3 is moved to emergencyposition, the measured inshot valve does not take part in theapplication. The first effect is venting of the brake pipe and emergencyresponse of the application valve to terminate feed to the brake pipe.'Ihis will produce an emergency application through emergency resp-onseofthe triple valves throughout the train. However, the response oftheapplication valve` starts a straight air application through the pipe12, double check valve I1, pipe 15 and decelerometer I6 to the controlchamber` |8, which then functions through the master relays. As stated,the straight air or control pipe I2 will assume control of the localrelays if an effective pressureis developed in it, irrespective of theresponse of the 'triple valve. Thus, an emergency application occasionedin any way will be decelerometer controlled 'if the straight air side ofthe' system functions.

While a particular embodiment of this invention and its use with aparticular system have been described in detail, this is intended to beillustrative and not limiting.

What lis claimed is: i

1. In a train brake system, the combination of a brake controlling relaymechanism lincluding a control chamber, so arranged` that pressuresestablished therein operate the relay to effect a related control ofbraking; a sourceof pressure fluid; an engineers brake valve having arelease position in which it serves to vent said control chamber, and aslow application position in which it supplies pressure fluid from saidsource to said chamber at a restricted rate; and means renderedeffective by motion of the engineers brake valve from release to slowapplication position to raise control chamber pressure rapidly through alimited range.

2. In a train brake system, the combination of a brake controlling relaymechanism including a control chamber, so arranged that pressuresestablished therein operate the relay to effect a related control ofbraking; a source of pressure fluid; an engineers brake valve having arelease position in which it serves to vent said control chamber, and aslow application position in Vwhich it supplies pressure uid from saidsource to said chamber at a restricted rate; and means renderedeffective by motion oi thev engineers brake valve from release to slowapplication position to admit to the control chamber a definite volumeof pressure fluid at supply pressure.

f3; Thecombination of a brake controlling relay valve mechanism having acontrol chamber; a

source of pressure fluid; an engineers brake "valve for admittingpressure iiuid from said lsource to said control chamber and forexhausti'rig pressure fluid from said control chamber; a measuringchamber normally connected with said source to be charged therefrom; andmeans responsivet'o the initial flow of pressure iluid lrom'theengineers` brake valve toward the control chamber to disconnect saidmeasuring chamber from said source and connect it with said controlchamber, and thereafter responsive to controlchamber pressure tomaintain such connection until Vcontrol chamber pressure has beensubstantially released, and then disconnect `the measuring chamber fromthe control chamber and reconnect it with said source.

' 4V AThe combination of a brake controlling relay valve mechanismhaving a control chamber; a sourcefof pressure fluid; an engineers brakevalve for admitting pressure fluid from said source to said controlchamber and for exhausting pressure fluid from said control chamber; ameasuring chamber normally connected with said source to be .chargedtherefrom; an intercepting valve interposed in a passage between theengineers brake valve and` the control chamber to control flowtherebetween; means biasing said valve in a closing direction; anabutment connected with said Valve subject to pressure flowing from saidengineers brake valve toward said intercepting valve Yand serving underthe urge of such pressure `to open said intercepting valve; and a valvevalve for admitting pressure fluid from said ing pressure fluid fromsaid control chamber; a

source to said control chamber and for exhaustmeasuring chamber normallyconnected with said source to be charged therefrom; an intercepting.valve interposed in a passage between the engineers brake valve and thecontrol chamber to control flow therebetween; means biasing said valvein a closing direction; an abutment connected with said valve subject topressure flowing from said engineers brake valve toward saidintercepting valve and serving under the urge of such pressure to` opensaid intercepting valve; a valve mechanism for selectively connectingsaid measuring chamber with said source and with said control chamberand arranged to be actuated by said abutment, the parts being soarranged that when Vthe intercepting valveis open, the measuring chamberis connected with the control chamber, and when the intercepting Valveis closed the measuring chamber is connected with the source ofvpressure fluid; a pair of reversely seated check valves controlling abypass around said intercepting valve; and means for loading said bypassvalves in closing directions, the loading for that bypass valve whichopens to permit flow toward the engineers brake valve being light, andthe loading of the bypass check valve which permits flow in the reversedirection being heavier and sufcient to hold the check valve closedagainst a pressure sufficient to displace said abutment.

6. The combination with the structure dened in claim 3, of a modulatingvalve responsive to deceleration produced by a brake application andserving to control the deceleration rate by closing communicationbetween the engineers brake valve and the control chamber and modulatingcontrol chamber pressure, the volume of the measuring chamber being sorelated to the volume of the control chamber that the brake applyingtendency initiated by connection of the measuringv chamber with thecontrol chamber is insufficient to produce a retardation to which saiddeceleration controller will respond.

'7. The combination with the structure defined in Claim 4, of amodulating valve responsive to deceleration produced by a brakeapplication and serving to control the deceleration rate by closingcommunication between the engineers brake valve and the control chamberand modulating control chamber pressure, the volume of the measuringchamber being so related to the volume of the control chamber that thebrake applying tendency initiated by connection of the measuring chamberwith the control chamber is insufficient to produce a retardation towhich said deceleration controller will respond.

8. The combination with the'structure dened in claim 3, of Va normallycharged brake pipe; and an application valve responsive to the depletionof pressure in said brake pipe to admit air from said source directly tosaid control chamber, whereby the brake applying function of theapplication valve is unaffected by said means responsive to initialflow.

9. The combination with the structure dened in claim 3, of a`normallycharged brake pipe; and an application and vent Valve mechanismresponsive to depletion of brake pipe pressure to vent the brake pipe,suspend charging of the brake pipe, and admit pressure fluid from saidsource to said control chamber directly, said engineers brake valvehavingnan emergency position in whichit causes operation of saidapplication andvent valve.

10. The combination of a relay mechanism for controlling air brakes andhaving a control chamber; a source ofpressure fluid; an engineers brakevalvek having a slow service position in "which it supplies pressureiiuid at a restricted rate to said control chamber, a fast serviceposition inwhich it admits pressure fluid at a rapid rate from saidsource to said control chamber, and a release position in which it ventsfluid from .said control chamber; a measuring chamber normally'connectedwith said source; an intercepting lvalve interposed in the communicationbetween the engineers brake valve and said control chamber; .meansbiasing said valve in a closing direction; Va movable abutment subjectto .pressure iluid flowing from the engineers brake valve toward thecontrol chamber and serving in response tosuch pressure to open saidintercepting valve; valve means operable by said abutment and 4servingwhen saidintercepting Valve is closed to connectsaid measuring reservoirwith said source of fluid pressure and disconnect it from said controlchamber, and serving when said intercepting valve is open `to isolatesaid measuring chamber from said source and connect the measuringchamber `with the control chamber; and a pair of reversely seated bypasscheck valves controllinga bypass around said intercepting valve, thebypass check valve which permits the releasing flow toward the engineersbrake valve being lightly loaded, and the bypass check which permits owtoward the control chamber being loaded sufficiently to insure responseof said abutment to pressure fluid flowing m; toward the controlchamber, whereby the intercepting valve controls flow in slow serviceposition, and the bypass check valve opens to permit rapid flow in fastservice position.

inshot Valve mechanism having two functional positions in one of whichit charges said measuring chamber from said source, and in the other ofwhich it disconnects said measuring chamber from said source andconnects it directly with said control chamber; means biasing saidinshot 4valve to the rst named position; motor means `adapted `tobeoperated by pressure fluid supplied by said engineers brake valve andflowing toward said control chamber to shift said inshot e valvemechanism to the second named position;

and a valve associated with said motor and arranged to resist flow fromsaid engineers brake `valve to said control chamber until said motor hasshifted said inshot valve mechanism to the i second named position. A

12. In a braking system, the combination of a relay mechanism having acontrol chamber and arranged to control application and release of thebrakes throughout a train in accordance with pressures in said chamber;a source of pressure fluid; an engineers brake valve adapted to supplypressure iluid at at least two different rates one slow and anotherrapid from said source to said fcontrol chamber and to exhaust pressurefluid from said control chamber; a measuring chamber; an inshot valvemechanism having two functional positions in one of which it chargessaid measuring chamber from said source, and in the other of which itdisconnects said measuring chamber from said source and connects itdirectly with said control chamber; means biasing said inshot valve tothe rst named position; motor means adapted to be operated by pressurefluid supplied by said engineers brake valve and flowing toward saidcontrol chamber to shift said inshot valve mechanism to the second namedposition; a valve associated with said motor and arranged to resist flowfrom said engineers brake valve to said control chamber until said motorhas shifted said inshot valve mechanism to the second named position;and a loaded check valve mechanism controlling a one-way bypass from theengineers brake valve directly to the control chamber, the loading ofsaid valve being such as to hold the bypass valve closed when theengineers brake valve feeds air at a restricted rate and to` open andpermit rapid ow when the engineers brake valve supplies air at a rapidrate.

13. In a braking system, the combination of a relay mechanism having acontrol chamber and arranged to control application and release of thebrakes throughout a train in accordance with pressures in said chamber;a source of pressure liuid; an engineers brake valve adapted to supplypressure iiuid at two different rates, one slow and the other rapid,from said source to said control chamber and to exhuast pressure fluidfrom said control chamber; a measuring chamber; an inshot valvemechanism having two functional positions in one of which it chargessaid measuring chamber from said source, and in the other of which itdisconnects said measuring chamber from said source and connects itdirectly with said control chamber; means biasing said inshot valve tothe first named position; motor means adapted to be operated by pressureiluid supplied by said engineers brake valve and flowing toward saidcontrol chamber to shift said lnshot valve mechanism to the second namedposition; a valve associated with said motor and arranged to resist flowfrom said engineers brake valve to said control chamber until said motorhas shifted said inshot valve mechanism to the second named position; aloaded check valve controlling a one-way by-pass from the engineersbrake valve directly to the control chamber, the loading of said valvebeing such as to hold the by-pass valve closed when the engineers brakevalve feeds air at a restricted rate and to open and permit rapid flowwhen the engineers brake valve supplies air at a rapid rate; and asecond and relatively reversely seated check valve controlling a directcommunication from the control chamber to the engineers brake valve andadapted to open and permit substantially free Vexhaust of said controlchamber in the releasing position of said engineers brake Valve.

CHARLES A. CAMPBELL.

